by Robert Bianco, USA TODAY

by Robert Bianco, USA TODAY

In competing yet divergent ways, a sudden, dominant urge to get ahead has been the driving force this season behind this fabulous show's two main characters, Raylan and Boyd - so extraordinarily played by Timothy Olyphant and Walton Goggins.

For Raylan, a desire to provide for his unborn child led him to try out multiple moneymaking schemes before finally settling on career advancement. For Boyd, a longing for a better life for his and Ava's yet-to-be-conceived children caused him to set his criminal sights on a house in the suburbs and an eventual move to more legitimate businesses. Like, for example, a Dairy Queen franchise, a telling example of the show's near-pitch-perfect ability to tell a joke that sheds new light on characters without violating what we already know about them.

Still, the most important display of successfully realized ambition has come from the show's writers - some of the best working on TV today - who refreshed this FX hit (tonight, 10 ET/PT) by temporarily doing away with a "big bad" season-long nemesis for Raylan. It was both a bold and a wise move: bold, because it went against viewer expectations; wise, because it rescued the show from the trap of trying to top itself each year with ever bigger and badder villains.

In place of a single central story, Justified has offered smaller self-contained arcs, laced throughout with Boyd and Raylan's chase for the missing (and now found) Drew Thompson. Twists have been set into play by Detroit mobster Theo Tonin, but he's pulled strings from behind the scenes, as is fitting for the folks in Harlan County, Ky., who feel like the powers controlling their lives are as distant as they are invisible.

As with Boyd's running battle with the county's social upper crust, this outsider-as-carpetbagger story exemplifies Justified's willingness to explore life in a corner of America that TV usually either avoids or exploits for comic stereotypes.

Drew, we now know, is actually Harlan's sheriff, Shelby, and is in Raylan's custody. In tonight's episode, written by the show's creator, Graham Yost, and Chris Provenzano, Raylan's job is to keep him alive long enough to get him out of town.

It's an hour that encapsulates, as much as any one hour can, most of the virtues that make this show not just one of TV's best but one of its most enjoyable as well, two qualities that do not always go hand in hand. The plot barrels forward on multiple tracks, with each of Boyd's moves to take Drew countered by Raylan, and every tense moment offering unexpected flashes of humor and dreaded outbursts of violence. And pulsating around the story is the oddly amusing, symbiotic relationship between Raylan and Boyd, whose distaste for each other is only topped by their mutual dislike of outsiders.

As always, there's the intense pleasure of spending time with one of the best ensembles TV has to offer. That joy starts with Olyphant and Goggins, then stretches through to the core support of Nick Searcy, Joelle Carter, Jacob Pitts and Erica Tazel. As a bonus tonight, you get great guest work by Jere Burns, Ron Eldard, Mike O'Malley, Jim Beaver and - most especially - Patton Oswalt, whose Constable Bob may hold the key to Raylan and Boyd's futures.

That may come as a surprise to some viewers, as on most shows, Bob would be no more than a joke. Justified sees through the comedy to the humanity in the character, and then shows us even more. That's more than just ambition; it's ambition fulfilled.